Boeing 757-222 incident near Grand Junction, Colorado, February 14, 1993
On February 14, 1993 at about 2:15 am local time, a Boeing 757-222, registered N508UA, was involved in an incident near Grand Junction, Colorado. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 47 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
FAILURE OF THE LEFT GENERATOR CONTROL UNIT (GCU), INTEGRATED DRIVE GENERATOR (IDG), RIGHT (SIDE) ENGINE INDICATOR AND CREW ALERT SYSTEM (EICAS), AND BUS TIE BAR (BTB).
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 14, 1993 · about 2:15 am local time
- Place
- Grand Junction, Colorado · map
- Type
- Incident
- Injuries
- No one was hurt; 47 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 757-222 · all 757-222s on the register
- Registration
- N508UA · registry record · serial 24744
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
WHILE CRUISING AT FL390, THE AUTOTHROTTLES AND AUTOPILOT DISENGAGED, THE CAPTAIN'S INSTRUMENTS FAILED, AND THE COCKPIT LIGHTING CYCLED ON AND OFF. THE LEFT GENERATOR LIGHT ILLUMINATED, THE EICAS FAILED, A CYCLIC BANGING WAS HEARD, AND AN ACRID ODOR WAS NOTICEABLE. THE LEFT AC BUS AND TRANSFER BUS WERE DEENERGIZED AND THE CAPTAIN ELECTED TO DIVERT TO THE NEAREST SUITABLE AIRPORT. POST INCIDENT INVESTIGATION DISCLOSED A SHORTED DIODE IS THE LEFT GCU (GENERATOR CONTROL UNIT), A DEFECTIVE IDG (INTEGRATED DRIVE GENERATOR), A SHORT IN THE INPUT POWER FILTER IN THE EICAS (ENGINE INDICATOR AND CREW ALERT SYSTEM), AND A DEFECTIVE BTB (BUS TIE BAR).
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 11,698 hours in all; 410 in this make and model; 155 in the last 90 days; 59 in the last 30 days
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 9,483 hours
- Last inspection: continuous airworthiness programme, January 14, 1993; 284 hours since
- Maximum gross weight: 231,000 lb
- Seats: 252
- Landing gear: retractable
- Engine: P&W 2037-717 (turbofan); 0 hours total
- Operator: United Airlines
The flight
- Departed from: PHL Philadelphia PA at 3:22 am
- Destination: LAX Los Angeles CA
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: night, dark
- Wind: from 320° at 5 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 32°F (0°C), dew point 21°F (-6°C)
- Altimeter: 30.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 7 | |||
| Passengers | 40 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N508UA the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.